Richard T Wiedmann

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M-M-R™II (measles, mumps, and rubella virus vaccine live; Merck, Sharp, & Dohme Corp.) is indicated for simultaneous vaccination against measles, mumps, and rubella in individuals ≥ 12 months of age. Before the vaccine era, these viruses infected most exposed individuals, with subsequent morbidity and mortality. One of the greatest achievements of public(More)
Previous work has characterized the Purkinje-ventricular junction (PVJ) of papillary muscles as a region of low safety factor with some delay between P and V activation. We have previously shown that the P strand action potential activates a layer of P cells over most of the papillary muscle surface, but activation of the underlying V cells occurs only at(More)
UNLABELLED Vaniprevir (MK-7009) is a macrocyclic hepatitis C virus (HCV) nonstructural protein 3/4A protease inhibitor. The aim of the present phase II study was to examine virologic response rates with vaniprevir in combination with pegylated interferon alpha-2a (Peg-IFN-α-2a) plus ribavirin (RBV). In this double-blind, placebo-controlled, dose-ranging(More)
In open-chest anesthetized dogs, the time constant of isovolumic left ventricular pressure decay increased following the intravenous administration of either E4031, a class III antiarrhythmic agent which acts by K+ channel blockade, or DPI 201-106 (DPI), a cardiotonic agent which acts by delaying Na+ channel inactivation. In addition to prolonging cardiac(More)
Quercetin had a biphasic effect on Ca2+ uptake and calcium-stimulated ATP hydrolysis in isolated cardiac sarcoplasmic reticulum (SR). Stimulation of Ca2+ATPase was observed at low quercetin concentrations (<25 microM) followed by inhibition at higher concentrations. The effects were dependent upon the SR protein concentration, the MgATP concentration, and(More)
We have studied the individual and combined effects of elevated external potassium concentration (8 mM [K+], metabolic acidosis (pH = 6.8), and hypoxia at different stimulation 400 milliseconds) on Purkinje (P) and ventricular (V) conduction velocities and on Purkinje-ventricular junctional conduction delay (PVJ delay) in in vitro preparations from canine(More)
To determine whether growth hormone (GH) replacement improves cardiac function, GH-deficient hypophysectomized rats with moderate myocardial infarction (MI) were studied after 3 wk of treatment with either recombinant rat GH (3.2 mg.kg-1.day-1 sc) or vehicle. The serum insulin-like growth factor I level in rats after GH treatment was approximately 10-fold(More)
Conduction through the cardiac syncytium varies from being nearly continuous, with very well coupled cells, to being clearly discontinuous, with significant conduction delays over very short distances. The Purkinje-ventricular muscle junction (PVJ) sites on the endocardial surface have characteristic delays of conduction and the presence of discrete groups(More)
A heart failure model was developed using conscious pigs subjected to serial myocardial infarctions followed by intermittent rapid ventricular pacing. Aortic and atrial catheters, left ventricular (LV) pressure gauge, LV dimension crystals, ascending aortic flow probe, pacing leads, and two coronary artery occluders were implanted in 15 pigs. The initial(More)
Ablation of the gene for phospholamban (PLB), a transmembrane peptide regulator for the cardiac sarcoplasmic reticulum Ca2+ pump, in mice brings about a complete loss of the myocardial responses to beta-adrenergic agonists (e.g., Luo et al., Circ. Res. 1994; 75: 401). We have evaluated the functional significance of PLB-independent mechanisms in the(More)